Stenographic marking using network addressing

ABSTRACT

Systems, methods, apparatuses, and software for a content delivery network that caches content for delivery to end user devices is presented. In one example, a method includes establishing address translations which translate domain names into network addresses usable by the end user devices for reaching content at the cache nodes, with portions of the network addresses comprising stenographic information, and responsive to domain name translation requests from the end user devices, providing ones of the network addresses. The method includes receiving content requests transferred by the end user devices that comprise the network addresses, and performing one or more actions based on the stenographic information in the network addresses.

RELATED APPLICATIONS

This application hereby claims the benefit of and priority to U.S.Provisional Patent Application 62/261,447, titled “STENOGRAPHIC MARKINGUSING NETWORK ADDRESSING,” filed Dec. 1, 2015, and which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

Aspects of the disclosure are related to the field of communicationnetworks, and in particular content delivery and routing of content overcommunication networks.

TECHNICAL BACKGROUND

Network-provided content, such as Internet web pages or media contentsuch as video, pictures, music, and the like, are typically served toend users via networked computer systems. End user requests for thenetwork content are processed and the content is responsively providedover various network links. These networked computer systems can includeorigin hosting servers which originally host network content of contentcreators or originators, such as web servers for hosting a news website.However, these computer systems of individual content creators canbecome overloaded and slow due to frequent requests of content by endusers.

Content delivery networks have been developed which add a layer ofcaching between origin servers and end users. The content deliverynetworks typically have one or more cache nodes distributed across alarge geographic region to provide lower latency access to the contentfor the end users. When end users request content, such as a web page,which is handled through a cache node, the cache node is configured torespond to the end user requests instead of the origin servers. Contentdelivery networks can also support Internet Protocol version 6 (IPv6),which has been established to overcome some of the shortcomings withIPv4, namely total address space limitations as well as other protocollimitations. IPv6 incorporates a 128-bit address instead of the 32-bitaddress of IPv4, and IPv6 has now been implemented in most networkrouting equipment.

In some instances, end user devices may be configured to “attack”content delivery equipment by repeatedly and frequently requestingcontent from a content provider, or cause the equipment to process manycontent-related tasks at once, among other operations. For example,during a network bot attack, a denial of service (DoS) attack, or adistributed denial of service (DDoS) attack, one or more end userdevices can request network content at a frequent pace so as to overloador crash network equipment. In cases where an origin server alone servesthe network content, the origin server can quickly become overloaded bythe frequent content requests and crash. Cache nodes can alleviate theburden on origin servers to defend against these attacks, however, cachenodes can have difficulty in blocking traffic related to attacks.

OVERVIEW

Systems, methods, apparatuses, and software for a content deliverynetwork (CDN) that caches content for delivery to end user devices ispresented. In one example, a method includes establishing addresstranslations which translate domain names into network addresses usableby the end user devices for reaching content at the cache nodes, withportions of the network addresses comprising stenographic information,and responsive to domain name translation requests from the end userdevices, providing ones of the network addresses. The method includesreceiving content requests transferred by the end user devices thatcomprise the network addresses, and performing one or more actions basedon the stenographic information in the network addresses.

In another example, a CDN having a plurality of cache nodes that cachecontent for delivery to end user devices is presented. The CDN includesa stenography node configured to establish address translations for theend user devices which translate domain names into network addressesused for reaching content at selected cache nodes, with portions of thenetwork addresses comprising stenographic information. The stenographynode is configured to provide the address translations to at least onedomain name system (DNS) node that provides ones of the networkaddresses responsive to domain name translation requests from the enduser devices. At least one of the cache nodes is configured to receivecontent requests transferred by the end user devices that comprise thenetwork addresses, and perform one or more actions based on thestenographic information in the network addresses.

In another example, a method of operating a stenography node of acontent delivery network that caches content for delivery to end userdevices is provided. The method includes establishing addresstranslations for the end user devices which translate domain names intonetwork addresses used for reaching content at selected cache nodes,with portions of the network addresses comprising stenographicinformation used to distinguish among a plurality of DNS nodes whichprovide ones of the network addresses responsive to domain nametranslation requests from the end user devices. The method includesinstructing one or more cache nodes to perform one or more actions basedon the stenographic information in the network addresses responsive toreceiving content requests transferred by the end user devices thatcomprise the network addresses.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present disclosure. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the views. While multiple embodiments are described inconnection with these drawings, the disclosure is not limited to theembodiments disclosed herein. On the contrary, the intent is to coverall alternatives, modifications, and equivalents.

FIG. 1 illustrates a communication system.

FIG. 2 illustrates a method of operating a communication system.

FIG. 3 illustrates an example address space.

FIG. 4 illustrates a communication system.

FIG. 5 illustrates a method of operating a communication system.

FIG. 6 illustrates a communication system.

FIG. 7 illustrates a method of operating a communication system.

FIG. 8A illustrates a method of operating a communication system.

FIG. 8B illustrates a method of operating a communication system.

FIG. 9 illustrates a cache node.

FIG. 10 illustrates a control node.

DETAILED DESCRIPTION

Network content, such as web page content, typically includes contentsuch as text, hypertext markup language (HTML) pages, pictures, video,audio, code, scripts, or other content viewable by an end user in abrowser or other application. This various network content can be cachedby the cache nodes of a content delivery network. The network contentcan include website content, pictures, video, other media, dynamiccontent, and other content, including combinations thereof.

Content delivery networks can add a layer of caching between originservers of the content providers and the end users. The content deliverynetworks typically have one or more cache nodes distributed across alarge geographic region to provide lower latency local access to thecontent for the end users. When end users request content, such as a webpage, a selected cache node will respond to the content request insteadof the associated origin server. Various techniques can be employed toensure the cache node responds to content requests instead of the originservers, such as associating web content of the origin servers withnetwork addresses of the cache nodes instead of network addresses of theorigin servers using domain name system (DNS) registration and lookupprocedures. Although cache nodes and origin servers are shown asdifferent nodes in the examples herein, it should be understood that theorigin servers and cache nodes can be included in one or more of thesame nodes.

Internet Protocol version 6 (IPv6) has been established to overcome someof the shortcomings with IPv4, namely total address space limitations aswell as other protocol limitations. This address space can be leveragedas IPv6 becomes implemented in more network elements and routingequipment. IPv4 provides 32-bit IP addressing, while IPv6 uses 128-bitaddressing, providing for 2¹²⁸ uniquely identifiable addresses. IPv6addresses are represented as eight groups of four hexadecimal digitsseparated by colons, such as example IPv6 address 1111: FFFF: 2222:EEEE: 3333: DDDD: 4444: CCCC. Other representations are possible, whichcan include more compact or less compact representations.

In some network routing examples, classless inter-domain routing (CIDR)can be employed, which includes a compact network address representationthat uses a “slash prefix” notation after an initial set of addressdigits. This notation indicates how many digits or bits are relevant forrouting associated packets, and routing equipment can use the quantityof digits indicated by the slash notation to select routing pathways.For example, an address with 1111: FFFF: 2222::/40 indicates that thefirst 40 bits of the IPv6 address are employed for routing purposeswhile the remaining bits are used for other purposes, such as localrouting, routing within a point-of-presence (POP), or other purposes.IPv4 can use different notations than IPv6, however the examples belowwill mainly employ IPv6 notations. The number of digits uses in theslash notation can vary, and typically only a maximum of 48 bits areemployed in a prefixed notation, namely 1111:FFFF:2222::/48. Theremaining bits in an IPv6 address, such as the least-significant 64bits, can be used for local routing, among other uses. In the examplesherein, a portion of the bits used in IPv6 addresses are employed forencoding various information and instructions, such as will be discussedbelow for the stenography, anonymization, and attack mitigationexamples.

As a first example employing a content delivery network, FIG. 1 ispresented. FIG. 1 is a system diagram illustrating communication system100. Communication system 100 includes one or more user devices 120-122,content delivery network (CDN) 110, one or more origin servers 130, anddomain name system (DNS) 140. CDN 110 further includes a plurality ofcache nodes 111-112, DNS node 113, and stenography node 115. Cache nodes111-112 can be arranged at one or more physical sites orpoints-of-presence (POPs), among other arrangements. Cache nodes 111-112provide content to end user devices 120-122 over various network linksand packet networks, such as shown for packet links 150-151. Cache nodes111-112 cache content for delivery to end user devices 120-122, wherethe content may be originated at origin server 130, among other originservers and systems. In this example, content associated with web pages160-161 can be cached by cache nodes 111-112.

In operation, an end user device, such as end user device 120, browsescontent in a user application, such as a web browser, mobile app, orother application. This content is referenced by a domain name, uniformresource locator (URL), uniform resource identifier (URI), or otheridentifier. Typically, these identifiers are not numerical networkaddresses, and the end user device must perform a domain name system(DNS) translation process to receive a numerical network address whichcan be used to request content and is routable by network routingelements.

This DNS process includes transferring a DNS query message to a DNSsystem or DNS node that serves the end user device. This DNS querymessage indicates at least a domain name which is to be translated intoa network address. This DNS query message can be forwarded or recursedto further DNS nodes, such as DNS node 113 associated with CDN 110. InFIG. 1, end user device 120, for example, can issue DNS query 104 fordelivery to DNS system 140. DNS system 140 can recurse this DNS query toDNS node 113 of CDN 110 in DNS query 105. DNS node 113 returns a networkaddress to DNS system 140 which is then delivered to end user device120. End user device 120 can then issue one or more content requests 106for content associated with the domain name using packets addressedusing the network address received in the DNS query process. One of thecache nodes of CDN 110 can receive the content requests and respond withcontent for delivery to end user device 120.

However, end user device 120 might be a malicious device, such as anetwork attacker performing a denial-of-service (DoS) attack orassociated with a distributed denial-of-service (DDoS) attack. In otherexamples, specialized functions or operations might be desired forhandling or responding to content requests from a particular end userdevice. In FIG. 1, information can be encoded into the network addressesprovided to end user devices to indicate specialized functions or toinclude various information when content requests using those networkaddresses are received by cache nodes. This can be referred to asstenography, and stenographic information is encoded into a portion ofthe network addresses.

In IPv6 network addresses, as discussed above, 128 bits are employed toaddress an endpoint. However, in the examples herein, an upper portionis employed to route traffic to a particular cache node of CDN 110. Thisupper portion can be indicated by a prefixed portion of an IPv6 address,such as a shown in FIG. 3 for /40 thru /64 prefixed addresses. A lowerportion can be used to encode various information or functions as willbe discussed below.

To provide another example operation of the elements of system 100, FIG.2 is presented. In FIG. 2, stenography node 115 establishes (201) enduser device address translations which translate domain names intonetwork addresses used for reaching content at selected cache nodes, thenetwork addresses comprising stenographic information. Example addresstranslations are shown in FIG. 1 as configuration 103. IPv6 addressstructure 101 in FIG. 1 shows an upper portion of bits and a lowerportion of bits, with the lower portion reserved for functional bits andused to encode stenographic information. Stenography node 115 can encodeor otherwise incorporate stenographic information into these functionalbits.

Specifically, configuration 103 includes three user addresses which canbe provided to end user devices 120-122 for reaching content cached byones of cache node 111-112. These address translations provide fortranslation between domain names or other URL information and networkaddresses.

The stenographic information can comprise various encoded information,which can be included in network addresses of content requests issued byend user devices, and once received, interpreted by cache nodes 111-112or transferred to stenography node 115 for interpretation. Thestenographic information can be encrypted, scrambled, or otherwiseencoded into an IPv6 address. The stenographic information can includeidentifiers, such as watermarking information, to track end users orcontent request for certain content providers, domain names, or to trackwhich networks are used to route content requests, among other trackinginformation. The stenographic information can indicate functions oractions to be taken responsive to receiving content requests thatinclude the stenographic information, such as logging functions, traffichandling functions, traffic blocking functions, or other functions.These functions can be executed by cache nodes or other nodes in CDN110. The stenographic information can be established per-contentrequest, per-packet, per-user application, per-content/domain,per-website, per-end user identity, among others.

Stenography node 115 can provide these translations to DNS node 113 ofCDN 110 to be used for DNS queries or DNS translation requests.Responsive to domain name translation requests transferred by the enduser devices, DNS system 113 provides (202) ones of the networkaddresses. DNS system 113 can receive these domain name translationrequests as recursed ones from DNS system 140 in some examples, or mightreceive them without a recursive structure. As seen in FIG. 1, end userdevice 120 receives content address 191 responsive to a DNS translationrequest, such as for a domain name associated with web page 160 or 161.End user device 121 receives content address 192 responsive to a DNStranslation request, such as for a domain name associated with web page160 or 161. End user device 122 receives content address 193 responsiveto a DNS translation request, such as for a domain name associated withweb page 160 or 161.

Once end user devices 120-122 receive any associated domain nametranslations, these user devices can include the provided networkaddresses (which include the stenographic information) in contentrequests to retrieve content. Cache nodes 111-112 receive (203) thecontent requests transferred by the end user devices that comprise thenetwork addresses. Cache nodes 111-112 perform (204) one or more actionsbased on the stenographic information in the network addresses. As seenin FIG. 1, content address 191 is received by cache node 111, andassociated with function A. Content address 192 is received by cachenode 111, and associated with function B. Content address 193 isreceived by cache node 112, and associated with function C. Thesefunctions are then performed at the associated cache node or indicationsof the functions can be provided to stenography node which performs thefunctions. As mentioned above, the functions can include specializedtracking, logging, traffic handling, traffic dropping, or otherfunctions.

Advantageously, elements of CDN 110, such DNS resolver nodes, can returnspecially-crafted IP addresses for a subset of DNS queries. At least aportion of each of the IP addresses can be encoded by the DNS resolveror control node in order to mark, or taint, any subsequent contentrequests. For example, if an operator of CDN 110 suspects maliciousrequests are being received from a specific locality ‘A’ (e.g., ISP ‘C’in Virginia) for a specific service ‘X’ (such as web page 160), then DNSnode(s) which are used by end user devices issuing DNS queries fromlocality ‘A’ can be singled-out by CDN 110. Specifically, DNS queriesfrom locality ‘A’ querying about service ‘X’ can responsively prompt theDNS node(s) to return IP addresses which get routed to a cache nodewhich caches service ‘X’. These IP addresses also encode additionalinformation or actions such as logging actions, traffic drop actions,among others. In the cache nodes which receive content requests with IPaddresses having the encoded information, the embedded actions can beperformed. This process allows CDN operators or customers to enforce ahigh level of functionality based on DNS responses, such as “log allcontent requests for my content/service which are coming from China,” or“drop all network traffic coming for content requests resolving fromoutside the US,” or “drop all network traffic for content requestsassociated with service ‘X’ which originate from locality ‘A’ for aspecified period of time. This process also makes possible toenforcement of DNS use. For example, if a network-based attacker keepsissuing attack traffic to a specific network address, CDN 110 mightselect to no longer return that address responsive to DNS queries.

As a specific example of the addressing employed in the examples herein,FIG. 3 is presented. FIG. 3 illustrates address space 300 which shows anexample breakdown of the 128-bit address space of an IPv6 address. Theprefixed indicators, such as /29, /40, /48, /64, and the like, indicatehow many of the most significant digits of the address are relevant forrouting purposes. For example, a /40 prefix indicates that theupper-most 40 bits of an address are considered.

In the example in FIG. 3, a /29 prefix corresponds to the entire contentdelivery network, and indicates that traffic should be routed to thecontent delivery network, such as CDN 110 in FIG. 1. A /40 indicates aparticular site. The site can comprise a geographic location but canalso have less physical distinctions that mere physicality. For example,a site can span more than one POP. A site might indicate a particulardata center or multiple data centers that serve a particular geographicarea or serve links groups by related traffic latencies. Cache nodegrouping /48 can indicate a particular cache node or collection of cachenodes which are in a load-balancing configuration and serve content.Local routing segregation /64 can segregate network traffic amongdifferent content types, such as video, audio, web page content, orother traffic segregations. For example, a /64 prefix can be employedfor content-provider specific segregation or tracking, or might beemployed for load balancing among cache nodes at a site or POP.Typically, only /48 specificity is reported to network providers inannouncement messages, and further prefixing is reserved for routinglocal to a site or within a POP or cache node. The remainingleast-significant bits in address space 300 beyond /64 can be employedfor functional endpoint addressing, such as network addresses forspecific endpoints, network interface cards, and the like. However, insome of the examples herein, these lower 64 bits can be employed forother purposes, such as functional addressing. This functionaladdressing can include attack mitigation, stenographic, and nodeanonymization, among others.

Returning to the elements of FIG. 1, CDN 110 can include multiple siteswhich each include one or more cache nodes. CDN 110 can also includenetwork routing equipment, packet handling equipment, network links,management systems, and other elements. Content delivery network 110handles delivery of network content to end user devices, such as enduser device 120. The network content includes web content, mediacontent, videos, audio, pictures, news, database information, and thelike. Cache nodes of content delivery network 110, such as cache nodes111-112, cache content for delivery to end user devices. The content canbe originated at various other systems, such as origin server 130. Insome examples, network content includes dynamic network content, andprocesses executed by cache nodes 111-112 create the dynamic content.

Cache nodes 111-112 can each include communication interfaces, networkinterfaces, processing systems, computer systems, microprocessors,storage systems, storage media, or some other processing devices orsoftware systems, and can be distributed among multiple devices.Examples of cache nodes 111-112 can each include software such as anoperating system, logs, databases, utilities, drivers, caching software,networking software, and other software stored on non-transitorycomputer-readable media.

End user devices 120-122 can be a user device, subscriber equipment,customer equipment, access terminal, smartphone, personal digitalassistant, computer, tablet computing device, e-book, Internetappliance, media player, game console, smartwatch, or some other usercommunication apparatus, including combinations thereof. Although oneend user device is shown in FIG. 1, it should be understood that anynumber of end user devices can instead be included, distributed over alarge geographic area, and each end user device can be distributed amongmultiple devices or virtual devices.

Origin server 130 can include communication interfaces, networkinterfaces, processing systems, computer systems, microprocessors,storage systems, storage media, or some other processing devices orsoftware systems, and can be distributed among multiple devices.Examples of origin server 130 can include software such as an operatingsystem, logs, databases, utilities, drivers, networking software, andother software stored on a computer-readable medium.

Stenography node 115 can include communication interfaces, networkinterfaces, processing systems, computer systems, microprocessors,storage systems, storage media, or some other processing devices orsoftware systems, and can be distributed among multiple devices.Examples of stenography node 115 can include software such as anoperating system, logs, databases, utilities, drivers, caching software,networking software, and other software stored on non-transitorycomputer-readable media.

DNS system 140 and DNS node 113 each performs IP address translationservices for end user devices, such as translating domain names into IPaddresses. In some examples, DNS system 140 delegates domain nametranslation to another DNS system, such as DNS node 113. In suchexamples, elements of DNS node 113 can be included in control node 140or other equipment. DNS system 140 and DNS node 113 can each includecommunication interfaces, network interfaces, processing systems,computer systems, microprocessors, storage systems, storage media, orsome other processing devices or software systems, and can bedistributed among multiple devices. Examples of DNS system 140 and DNSnode 113 can each include software such as an operating system, logs,databases, utilities, drivers, caching software, networking software,and other software stored on non-transitory computer-readable media.

Communication links 150-152 each use metal, glass, optical, air, space,or some other material as the transport media. Communication links150-152 can each use various communication protocols, such as wirelesscommunications, cellular communications, Long Term Evolution (LTE), IEEE802.11 (WiFi), Internet Protocol (IP), Ethernet, synchronous opticalnetworking (SONET), hybrid fiber-coax (HFC), circuit-switched,communication signaling, or some other communication format, includingcombinations, improvements, or variations thereof. Communication links150-152 can each be a direct link or can include intermediate networks,systems, or devices, and can include a logical network link transportedover multiple physical links. In some examples these intermediatenetworks include local Internet Service Providers (ISPs) through whichendpoints, such end user devices or origin servers, receive locallast-mile access to the Internet and to backhaul networks.

Links 150-152 can include one or more backhaul networks that eachcomprise one or more packet networks configured to route packetcommunications between endpoints over network links. Backhaul networkscan include routers, bridges, switches, management systems, networklinks, and other network routing and handling equipment, includingcombinations thereof. Each backhaul network is typically operated by adistinct service operator, service provider, or company to provideInternet routing services to a variety of customers. In some examples,each of backhaul networks comprise long-haul communication serviceproviders and route packet communications over network links betweensmaller local ISPs.

Although one main link for each of links 150-152 is shown in FIG. 1, itshould be understood that links 150-152 are merely illustrative to showcommunication modes or access pathways. In other examples, further linkscan be shown, with portions of the further links shared and used fordifferent communication sessions or different content types, among otherconfigurations. Communication links 150-152 can each include manydifferent signals sharing the same associated link, as represented bythe associated lines in FIG. 1, comprising resource blocks, accesschannels, paging channels, notification channels, forward links, reverselinks, user communications, communication sessions, overheadcommunications, carrier frequencies, other channels, timeslots,spreading codes, transportation ports, logical transportation links,network sockets, packets, or communication directions.

As another example of functional addressing to mitigate attacks, FIG. 4is presented. FIG. 4 is a system diagram illustrating system 400. System400 includes CDN 410 which includes cache sites 411-412, as well ascontrol node 415 and DNS node 419. System 400 includes Internet serviceproviders 405-406, backhaul providers 407-408, end user devices 420-422,and origin servers 430. Each backhaul providers 407-408 includes atleast one associated DNS node, namely DNS node 407A and 407B. Theelements of FIG. 4 can include similar elements as found in FIG. 1 andprovide further examples of the operation of the elements of system 100,although variations are possible.

Backhaul network providers 407-408 and ISPs 405-406 each comprise one ormore packet networks with various routers, packet links, and othernetwork elements which route traffic between endpoints. In someexamples, backhaul network providers 407-408 comprise long-haul packetnetworks which route network traffic between other networks, and can actas backbone networks. ISPs can comprise local last-mile networkproviders, and typically provide network or Internet access to end userdevices and other endpoint devices. and link those endpoints and devicesto backhaul networks, such as backhaul network providers 407-408. Links450-454 comprise one or more packet links which can include wired orwireless connections.

Cache sites 411-412 further comprise one or more cache nodes that can bearranged at one or more physical sites as shown in FIG. 4, or into oneor more logical groupings such as points-of-presence (POPs), among otherarrangements. For example, FIG. 4 shows two geographic regions, namelywith region ‘A’ 470 and region ‘B’ 461. These regions can have differentISPs and backhaul network providers, as well as sites or cache nodesassociated therewith. Site 411 might be located in or associated withregion 470, while site 412 might be located in or associated with region471. Other geographic or regional configurations are possible. The cachenodes provide content to end user devices 420-422 over various networklinks and packet networks, such as shown for packet links 450-153, ISPs405-406, and backhaul network providers 407-408. The cache nodes cachecontent for delivery to end user devices 420-422, where the content maybe originated at origin server 430, among other origin servers andsystems. In this example, content associated with web pages 460-461 canbe cached by the cache nodes.

In operation, an end user device, such as end user device 420, browsescontent in a user application, such as a web browser, mobile app, orother application. This content is referenced by a domain name, URL,URI, or other identifier. Typically, these identifiers are not numericalnetwork addresses, and the end user device must perform a domain namesystem DNS translation process to receive a numerical network addresswhich can be used to request content and is routable by network routingelements.

This DNS process includes transferring a DNS query message to a DNSsystem or DNS node that serves the end user device. This DNS querymessage indicates at least a domain name which is to be translated intoa network address. This DNS query message can be forwarded or recursedto further DNS nodes, such as DNS node 421 associated with CDN 410. InFIG. 4, end user device 420, for example, can issue a DNS query fordelivery to DNS node 407D. DNS node 407D can recurse this DNS query toDNS node 419 of CDN 410 in a DNS query. DNS node 419 returns a networkaddress to DNS node 407D which is then delivered to end user device 420.End user device 420 can then issue one or more content requests forcontent associated with the domain name using packets addressed usingthe network address received in the DNS query process. One of the cachenodes of CDN 410 can receive the content requests and respond withcontent for delivery to end user device 420.

However, as shown in FIG. 4, end user device 420 might be a maliciousdevice, such as a network attacker performing a denial-of-service (DoS)attack or associated with a distributed denial-of-service (DDoS) attack.In IPv6 network addresses, as discussed above, 128 bits are employed toaddress an endpoint. However, in the examples herein, an upper portionis employed to route traffic to a particular cache node of CDN 410. Thisupper portion can be indicated by a prefixed portion of an IPv6 address,such as a shown in FIG. 3 for /40 thru /64 prefixed addresses. A lowerportion can be used to encode various information or functions tomitigate attacks or to identify locations, user devices, or otherproperties associated with an attack.

To provide another example operation of the elements of system 400, FIG.5 is presented. In FIG. 5, a method is presented which can identify andisolate attack traffic, such as network traffic associated withdenial-of-service attacks or distributed-denial-of-service attacks.Specifically, stenographic information is encoded into the lower-orderbits of an IPv6 address to allow DNS nodes and cache nodes to track,isolate, and perform other functions. To aid in targeted isolation ofattack traffic, first a localization process is performed to identifynetwork elements or physical locations associated with attack traffic.This localization process can localize attack traffic to a particularbackhaul network, ISP, end user device or collection of end userdevices. Since a cache node can serve many different end user devicesand those end user devices might not have a one-to-one relationshipbetween content requests and cache nodes, this process can identifyattack traffic as being associated with particular networks so thosenetworks or even endpoints can be isolated and mitigated while allowingnon-attack traffic to still be serviced. Thus, end user devices can bedirected to the same content or cache nodes but have differentstenographically-encoded network addresses which aid CDN 410 inmitigating network attacks. These encoded network addresses mightcomprise encoded instructions, encoded location information, orwatermarking which can be used to identify and partition particulartraffic.

Turning now to FIG. 5, control node 415 establishes (501) addresstranslations which translate domain names into network addresses usedfor reaching content at selected cache nodes, the network addressescomprising stenographic information. As shown in FIG. 1, IPv6 addressstructure 101 shows an upper portion of bits and a lower portion ofbits, with the lower portion reserved for functional bits and used toencode stenographic information. Control node 415 can encode orotherwise incorporate stenographic information into these functionalbits.

The stenographic information can comprise various information, which canbe included in network addresses of content requests issued by end userdevices, and once received, interpreted by cache nodes at sites 411-412or transferred to control node 415 for interpretation. The stenographicinformation can be encrypted, scrambled, or otherwise encoded into anIPv6 address. The stenographic information can include identifiers, suchas watermarking information, to track end users or content request forcertain content providers, domain names, or to track which networks areused to route content requests, among other tracking information. Thestenographic information can indicate functions or actions to be takenresponsive to receiving content requests that include the stenographicinformation, such as logging functions, traffic handling functions,traffic blocking functions, or other functions. These functions can beexecuted by cache nodes or other nodes in CDN 410. The stenographicinformation can be established per-content request, per-packet, per-userapplication, per-content/domain, per-website, per-end user identity,among other distinctions.

When control node 415 determines that malicious traffic or a networkattack should be mitigated, then further action can be taken by controlnode 415, and address translations can be tailored to mitigate theattack traffic. This mitigation can begin by first identifying alocality of from which the attack traffic originates or at least entersonto a particular ISP or backhaul network. This locality can include ageographic or physical locality, such as geographic region ‘A’ 470 andregion ‘B’ 471 shown in FIG. 4. This locality can include a logical ornetwork topological locality, such as indicated by the relationshipsbetween ISPs, backhaul providers, and other routing or logicalrelationships. Combinations of locality can be determined as well.

To aid in identifying a locality of the traffic, control node 415 canestablish address translations which are customized to a particulargeographic locality or network locality, and distribute these addresstranslations to DNS nodes associated with the various regions or networklocality. For example, control node 415 can establish addresstranslations for DNS node 407D and 408D which are different from eachother, and use different stenographic information in IPv6 addressesprovided to the two DNS nodes. This difference in address translationsand stenographic information can aid in localizing from which DNS nodethe address translations are requested. Control node 415 can providethese translations to DNS node 419 of CDN 410 to be used for DNS queriesor DNS translation requests.

DNS node 419 can be further provided with instructions by control node415 which are correlated to address translations or instructionsregarding handling of address translations. In this example, DNS queriescan be recursed to DNS node 419 from any of DNS node 407D or 408D, andDNS node 419 can perform actions based on various DNS query properties.These DNS query properties can include the domain name requested fortranslation, the source address of the DNS query (i.e. the address ofthe end user device which originally issued the DNS query), or uponother factors, such as indications that particular content isexperiencing malicious traffic-based attacks. These actions can beprompted by receiving a DNS query from DNS node 407D or 408D, or fromother sources. These actions can include logging information about theDNS queries, such as a time/day of receipt, a source address,intermediary network information including ISP, backhaul provider, ortop-level DNS node properties, a geographic region in which thetop-level DNS node is located, the domain name requested fortranslation, URI/URL properties of the DNS query, or other properties.These actions can include executing a particular function, such asdropping traffic associated with DNS requests or inhibiting response toDNS request for requests corresponding to particular domain names,particular source addresses or source address ranges, traffic associatedwith particular ISPs, backhaul provider networks, geographic regions, orother traffic properties. Alerts can be triggered by the aboveproperties which deliver alert messages to control node 415 or otherelements of CDN 410. In further examples, DNS node 419 mightresponsively transfer messages to DNS nodes 407D or 408D which commandDNS nodes 407D or 408D to remove a particular domain name or URL fromthe address translation tables or from CNAME records maintained orreferenced by DNS nodes 407D or 408D.

Responsive to domain name translation requests issued by the end userdevices, DNS node 419 can provide (502) selected ones of the networkaddresses. The DNS queries or DNS translation requests can be issued bythe end user devices responsive to user content browsing or to maliciousrequests, such as bots or DoS/DDoS malware, which can relate to contentassociated with example web pages 160 or 161, among other content. DNSnode 419 can receive these domain name translation requests, as recursedfrom any of DNS nodes 407D or 408D in some examples. As mentioned above,DNS node 419 can provide network addresses which include stenographicinformation in lower-order bits of the network addresses. Thestenographic information, can encode locality information or indicate aparticular function or functions to be executed by a cache node oncecontent requests using those network addresses are included in contentrequests issued by end user devices. DNS node 419 can also execute oneor more functions or actions based on the DNS queries, such as loggingDNS query properties, dropping DNS queries, among other actionsmentioned above.

If end user devices 420-422 receive domain name translations responsiveto DNS queries, these end user devices can include the provided networkaddresses (which include the stenographic information) in contentrequests to retrieve content. Cache nodes at sites 411-412 can receive(503) the content requests transferred by the end user devices thatcomprise the network addresses. In some examples, the cache nodes candeliver content responsive to the content requests, such as whenmalicious traffic is not associated with the content requests.

However, cache nodes at sites 411-412 can perform (504) one or moreprompted actions based on the stenographic information in the networkaddresses. Properties associated with the content requests can belogged. These properties can include the identities of the content beingrequested, source addressing of the content requests, time/day of thecontent requests, geographic locations associated with the contentrequests, intervening network properties, such as identities of ISPs orbackhaul network providers, among other properties.

When DDoS traffic is associated with the content requests, such as whenthe content requests are included in DDoS traffic 404 which is a part ofa malicious network-based attack, then further actions can be taken bythe cache nodes. For example, the stenographic information might includeinstructions, once decoded from the stenographic information, to logproperties associated with the malicious requests. The instructions mayindicate to drop content requests or ignore content requests whichinclude certain stenographic information. The instructions may indicateto transfer logged information to control node 415 or indicate variousproperties of the content requests to control node 415.

To identify any prompted instructions, indicators, or other informationcontained or encoded within the stenographic portions of the networkaddresses, cache nodes can process the network addresses against a listof addresses provided by control node 415 which correlates at leaststenographic content of network addresses to instructions, indicators,or other information. In other examples, a decode process is performedto translate the stenographic portions of the network addresses intodecoded portions which correspond to or indicate the instructions,indicators, or other information. In yet further examples, the cachenodes provide the stenographic portions to control node 415 for decodingand handling according to the instructions, indicators, or otherinformation. When the stenographic portions comprise encryptedinformation, then a decryption process can be performed by either thecache nodes or control node 415 to identify the instructions,indicators, or other information.

Advantageously, elements of CDN 410, such DNS node 419, can returncustomized IP addresses for a subset of DNS queries. At least a portionof each of the IP addresses can be encoded by the DNS node or controlnode in order to mark, or taint, any subsequent content requests. Forexample, if an operator of CDN 410 suspects malicious requests are beingreceived from a specific region ‘A’ (e.g., backhaul provider ‘C’ inOklahoma) for a specific service ‘Y’ (such as web page 461), then DNSnode(s) which are reached by end user devices issuing DNS queries fromregion ‘A’ can be isolated by CDN 410. Specifically, DNS queries fromregion ‘A’ querying about service ‘Y’ can responsively prompt DNS node419 to return IP addresses which get routed to a cache node which cachesservice ‘Y’. These IP addresses also include additional stenographicinformation which prompt actions such as logging actions, traffic dropactions, among others. In the cache nodes which receive content requestswith IP addresses having the stenographic information, the embeddedactions can be performed. This process allows CDN operators or customersto enforce a high level of functionality based on DNS responses, such as“log all content requests for my content/service which are coming fromregion A,” or “drop all network traffic coming for content requestsresolving from outside the region B,” or “drop all network traffic forcontent requests associated with service ‘Y’ which originate from region‘A’ for a specified period of time. This process also makes possible toenforcement of DNS use. For example, if a network-based attacker keepsissuing attack traffic to a specific network address, CDN 410 mightselect to no longer return that address responsive to DNS queries.

To further localize and isolate attack traffic, such as DDoS traffic 404in FIG. 4, an iterative process can be performed (505). For example, anetwork-based attack might be originating from particular regions orover particular network providers. Once an attack is detected by CDN410, then a subset or subsets of potential sources of the attack trafficare marked using the stenographic information in provided IP addressesand logged via a first DNS node which serves a first geographic area orlogical network partition, such as DNS nodes 407D or 408D which serve aparticular backhaul network provider which can serve specific regions.The first DNS node can transfer this log information to control node 415to identify localities, regions, or other network subdivisions fromwhich the attack traffic appears to be originating. Control node 415 canalso identify how much of the stenographically marked traffic iscomprised of attack traffic versus non-attack traffic at that first DNSnode, which can be identified by a ratio of attack/non-attack traffic,among other metrics. A second DNS node which serves a second geographicarea or logical network partition can be instructed to providestenographic IP addresses which can be used to identity furtherquantities of attack vs. non-attack traffic associated with the secondDNS node. All remaining DNS nodes can be iterated through to determineamounts of attack traffic associated with each region or partition. Insome cases, a particular DNS node might serve more than one geographicregion or network partition, or more than one DNS node might serve thesame geographic region or network partition. The iterative process canlocalize the attack traffic to a particular region or network partitionby selectively providing the stenographically-marked IP addresses overtime by the various DNS nodes. Once a threshold amount of attack trafficis detected by a particular DNS node, which can be localized using theiterative process, then those DNS nodes might be instructed to drop anyfurther DNS queries associated with a particular traffic property. Thetraffic property, as indicated above, can include traffic for aparticular domain name, for a particular content/service, for particularcache nodes, geographic regions, logical network partitions, or othertraffic properties, including combinations thereof.

In addition to stenographically marking network addresses, furtherfunctional addressing can be included in IP addresses. FIG. 6 ispresented to illustrate examples of endpoint anonymization using IPv6addresses. FIG. 6 is a system diagram illustrating communication system600. Communication system 600 includes one or more user devices 620-622,CDN 610, one or more origin servers 630. CDN 610 further includes aplurality of cache nodes 611-612, anonymization node 615, and DNS node619. Cache nodes 611-612 can be arranged at one or more physical sitesor POPs, among other arrangements. Cache nodes 611-612 provide contentto end user devices 620-622 over various network links and packetnetworks, such as shown for packet links 650-651. Cache nodes 611-612cache content for delivery to end user devices 620-622, where thecontent may be originated at origin server 630, among other originservers and systems. In this example, content associated with web pages660-661 can be cached by cache nodes 611-612.

In operation, an end user device, such as end user device 620, browsescontent in a user application, such as a web browser, mobile app, orother application. This content is referenced by a domain name, uniformresource locator (URL), uniform resource identifier (URI), or otheridentifier. Typically, these identifiers are not numerical networkaddresses, and the end user device must perform a domain name system(DNS) translation process to receive a numerical network address whichcan be used to request content and is routable by network routingelements.

This DNS process includes transferring a DNS query message to a DNSsystem or DNS node that serves the end user device. This DNS querymessage indicates at least a domain name which is to be translated intoa network address. In FIG. 6, end user device 620, for example, canissue a DNS query for delivery to DNS node 619. DNS node 619 might bereached using a recursed or hierarchical DNS structure with one or moreDNS nodes. DNS node 613 returns a network address to end user device620. End user device 620 can then issue one or more content requests forcontent associated with the domain name using packets addressed usingthe network address received in the DNS query process. One of the cachenodes of CDN 610 can receive the content requests and respond withcontent for delivery to end user device 620.

However, CDN 610 might desire to maintain anonymity and concealidentities among end user devices 620-622 or origin server 630 or toprevent blocking, throttling, monitoring, or identification of trafficassociated with CDN 610 by intervening backhaul networks, ISPs, or athird party. In IPv6 network addresses, as discussed above, 128 bits areemployed to address an endpoint. An upper portion is employed to routetraffic to a particular cache node of CDN 610. This upper portion can beindicated by a prefixed portion of an IPv6 address, such as a shown inFIG. 3 for /40 thru /64 prefixed addresses. In the examples herein forsystem 600, a lower portion can be used to anonymize endpointaddressing, as will be discussed below. The anonymization of the bits ofthe network addresses can be performed using randomization techniquessuch as random number generators, pseudo-random number generators, orother numerical randomization techniques. Typically, the anonymizationof the bits in the network addresses provides for ephemeral or temporarynetwork addresses which are periodically altered or generated.

To provide an example operation of the elements of system 600, FIG. 7 ispresented. In FIG. 7, anonymization node 615 establishes (701) end userdevice address translations which translate domain names into networkaddresses used for reaching content at selected cache nodes, the networkaddresses comprising stenographic information. Example addresstranslations are shown in FIG. 6 as configuration 603. IPv6 addressstructure 601 in FIG. 6 shows an upper portion of bits and a lowerportion of bits, with the lower portion reserved for functional bits andused to anonymize endpoints. Anonymization node 615 can anonymize thenetwork addresses using these functional bits.

Specifically, configuration 603 includes three anonymized user addresseswhich can be provided to end user devices 620-622 for reaching contentcached by ones of cache nodes 611-612. These address translationsprovide for translation between domain names or other URL informationand network addresses. Configuration 604 includes two anonymized originaddresses which can be provided to origin server 630 to retrieve contentfor web pages 660-661, and will be discussed below. Each network addressin configuration 603 and 604 comprises a different network address, witha first portion of upper address bits used for routing of associatedtraffic over backhaul networks, ISPs, and other networks like theInternet, while the lower order ‘functional bits’ are used foranonymization purposes. Thus, the upper address bits might not beanonymized, whereas the lower address bits are anonymized.

For content requests of end user devices, anonymization node 615 canestablish anonymized network addresses (701) and provide (702)relationships or correlations between domain names and anonymizednetwork addresses to DNS node 619. These anonymized network addressesare provided in response to DNS queries or DNS translation requests. Theaddress correlations can be tailored or individualized with respect tovarious factors. In a first example, each end user device is providedwith a different anonymized network address responsive to each DNSquery. Correlations between domain names and cache nodes orcontent/services can be established in anonymization node 615 andprovided to DNS node 619. In some cases, a list of many anonymizednetwork addresses are provided to DNS node 619 for use in individualresponses to DNS queries. Each DNS query for particular content canreturn a different anonymized address. In this manner, an identity of anend user device, content, and cache node can be concealed andanonymized.

CDN 610 routes (703) content requests comprising the anonymized networkaddresses to cache nodes based on the relationships between anonymizednetwork addresses and content. To route traffic with the anonymizednetwork addresses, the upper bits of associated IPv6 addresses can benon-anonymized and allow the traffic to be routed to CDN 610. However,routing within CDN 610 and associations with particular content or cachenodes still remain anonymized using the lower bits of associated IPv6addresses. Once received into CDN 601, one or more routing nodes, suchas routing node 616, can be provided with the correlations which allowrouting node 616 to direct content requests to proper cache nodes of CDN610 or can be used to de-anonymize the network addresses for usage androuting internal to CDN 610.

FIGS. 8A and 8B show further operations of CDN 610, in relation toretrieving origin content into cache nodes for caching of the origincontent. In FIG. 8A, content requests are issued by cache nodes toretrieve origin content from origin servers, such as origin server 630,and anonymized network addresses can also be employed. In this example,a DNS translation process typically is not needed for cache nodes toretrieve content from origin servers. The cache nodes typically willknow a network address for origin server 630 and can issue origincontent request using these addresses. However, intervening networkelements or packet networks might interfere with certain traffic orcertain traffic types once that traffic is identified, such as abackhaul network between cache node 612 and origin server 630 whichthrottles video content or other content.

Thus, to prevent unwanted throttling of identified traffic or to furtheranonymize endpoints associated with CDN 610, anonymization node 615 canestablish (801) anonymized network addresses for transfer of content tocache nodes of CDN 610 from origin servers, such as from origin server630. These anonymized network addresses can be periodically establishedfor each of the cache nodes of CDN 610 and used as source addresses incontent requests issued by cache nodes to retrieve origin content onorigin server 630. This can ensure anonymization of the return trafficfor content transferred by origin servers to the cache nodes.Correlations between the cache nodes and the anonymized networkaddresses can be provided (802) to routing node 616. Incoming networktraffic using these anonymized addresses can be routed (803) accordingto these relationships to ensure delivery of content transferred byorigin servers into the proper cache nodes which issued contentrequests.

Turning now to FIG. 8B, anonymization node 615 can be employed toprovide for further anonymization of origin content requests issued toorigin servers by cache nodes. In contrast to FIG. 8A which usesanonymized network addresses as source addresses in origin contentrequests issued by cache nodes, FIG. 8B discusses using furtheranonymized network addresses as destination network addresses to reachthe origin servers.

Anonymization node 616 periodically establishes (804) anonymized originnetwork addresses for cache nodes to reach origin servers, such asorigin server 630. These anonymized network addresses can be establishedfor each origin server, or can be based on other granularities, such asfor each content/server or website. However, in order for the origincontent requests to be properly delivered to origin servers, each originserver is periodically provided (805) with the anonymized networkaddress or addresses to which the origin servers are to respond. Also,routing elements of the various packet networks over which networktraffic is routed can be informed of the periodically altered networkaddresses. However, when only lower-order bits of network addresses areanonymized, then the routing elements might only be informed of changeswhen upper-level bits are altered which affect routing.

Cache nodes of CDN 610 can then issue (806) origin content requests toorigin servers using the anonymized origin network addresses. Originservers can responsively transfer the content to particular cache nodesbased on the source network addresses provided in the origin contentrequests.

Advantageously, the operations in FIGS. 8A and 8B provide for anonymizedtransfer of origin content between cache nodes and origin systems. Theseanonymized network addresses can be rotated periodically to preventidentification or throttling of traffic based on specific networkaddresses. Thus, temporary network addresses are employed in manyexamples. In some examples, it becomes possible to inspect addresses inheaders packets associated with network traffic to allow a networkoperator, network provider, or other entity to monitor or block networktraffic associated with certain services (such as particular websites orparticular types of content) without needing to inspect the datapayloads of the packets. Although this inspection and identification ofnetwork traffic might be desirable in some cases, in other cases itmight be desired to anonymize this network traffic to preventmonitoring, throttling, or blocking. For example, a backhaul networkprovider might throttle network traffic for a particular CDN or fortraffic of a particular website to allow another CDN or website toperform better. These anonymous and ephemeral identifiers can be usedfor content or services which CDN 610 prefers to not have identified intransit.

Returning to the elements of FIG. 6, CDN 610 can include multiple siteswhich each include one or more cache nodes. CDN 610 can also includenetwork routing equipment, packet handling equipment, network links,management systems, and other elements. Content delivery network 610handles delivery of network content to end user devices, such as enduser device 620. The network content includes web content, mediacontent, videos, audio, pictures, news, database information, and thelike. Cache nodes of content delivery network 610, such as cache nodes611-612, cache content for delivery to end user devices. The content canbe originated at various other systems, such as origin server 630. Insome examples, network content includes dynamic network content, andprocesses executed by cache nodes 611-612 create the dynamic content.

Cache nodes 611-612 can each include communication interfaces, networkinterfaces, processing systems, computer systems, microprocessors,storage systems, storage media, or some other processing devices orsoftware systems, and can be distributed among multiple devices.Examples of cache nodes 611-612 can each include software such as anoperating system, logs, databases, utilities, drivers, caching software,networking software, and other software stored on non-transitorycomputer-readable media.

End user devices 620-622 can be a user device, subscriber equipment,customer equipment, access terminal, smartphone, personal digitalassistant, computer, tablet computing device, e-book, Internetappliance, media player, game console, smartwatch, or some other usercommunication apparatus, including combinations thereof. Although oneend user device is shown in FIG. 6, it should be understood that anynumber of end user devices can instead be included, distributed over alarge geographic area, and each end user device can be distributed amongmultiple devices or virtual devices.

Origin server 630 can include communication interfaces, networkinterfaces, processing systems, computer systems, microprocessors,storage systems, storage media, or some other processing devices orsoftware systems, and can be distributed among multiple devices.Examples of origin server 630 can include software such as an operatingsystem, logs, databases, utilities, drivers, networking software, andother software stored on a computer-readable medium.

Anonymization node 615 can include communication interfaces, networkinterfaces, processing systems, computer systems, microprocessors,storage systems, storage media, or some other processing devices orsoftware systems, and can be distributed among multiple devices.Examples of anonymization node 615 can include software such as anoperating system, logs, databases, utilities, drivers, caching software,networking software, and other software stored on non-transitorycomputer-readable media.

DNS node 619 performs IP address translation services for end userdevices, such as translating domain names into IP addresses. In someexamples, a DNS system delegates domain name translation to DNS node619. DNS node 619 can include communication interfaces, networkinterfaces, processing systems, computer systems, microprocessors,storage systems, storage media, or some other processing devices orsoftware systems, and can be distributed among multiple devices.Examples of DNS node 619 can include software such as an operatingsystem, logs, databases, utilities, drivers, caching software,networking software, and other software stored on non-transitorycomputer-readable media.

Communication links 650-654 each use metal, glass, optical, air, space,or some other material as the transport media. Communication links650-654 can each use various communication protocols, such as wirelesscommunications, cellular communications, Long Term Evolution (LTE), IEEE802.11 (WiFi), Internet Protocol (IP), Ethernet, synchronous opticalnetworking (SONET), hybrid fiber-coax (HFC), circuit-switched,communication signaling, or some other communication format, includingcombinations, improvements, or variations thereof. Communication links650-654 can each be a direct link or can include intermediate networks,systems, or devices, and can include a logical network link transportedover multiple physical links. In some examples these intermediatenetworks include local Internet Service Providers (ISPs) through whichendpoints, such end user devices or origin servers, receive locallast-mile access to the Internet and to backhaul networks.

Links 650-654 can include one or more backhaul networks that eachcomprise one or more packet networks configured to route packetcommunications between endpoints over network links. Backhaul networkscan include routers, bridges, switches, management systems, networklinks, and other network routing and handling equipment, includingcombinations thereof. Each backhaul network is typically operated by adistinct service operator, service provider, or company to provideInternet routing services to a variety of customers. In some examples,each of backhaul networks comprise long-haul communication serviceproviders and route packet communications over network links betweensmaller local ISPs.

Although one main link for each of links 650-654 is shown in FIG. 6, itshould be understood that links 650-654 are merely illustrative to showcommunication modes or access pathways. In other examples, further linkscan be shown, with portions of the further links shared and used fordifferent communication sessions or different content types, among otherconfigurations. Communication links 650-654 can each include manydifferent signals sharing the same associated link, as represented bythe associated lines in FIG. 6, comprising resource blocks, accesschannels, paging channels, notification channels, forward links, reverselinks, user communications, communication sessions, overheadcommunications, carrier frequencies, other channels, timeslots,spreading codes, transportation ports, logical transportation links,network sockets, packets, or communication directions.

To further describe the equipment and operation of a cache node, FIG. 9is provided which illustrates cache node 900. Cache node 900 can be anexample of cache nodes 111-112 of FIG. 1, cache nodes of sites 411-412of FIG. 4, and cache nodes 611-612 of FIG. 6, although variations arepossible. Cache node 900 includes network interface 901 and processingsystem 910. Processing system 910 includes processing circuitry 911,random access memory (RAM) 912, and storage 913, although furtherelements can be included, such as discussed in FIGS. 1, 4, and 6.Example contents of RAM 912 are further detailed in RAM space 920, andexample contents of storage 913 are further detailed in storage system960.

Processing circuitry 911 can be implemented within a single processingdevice but can also be distributed across multiple processing devices orsub-systems that cooperate in executing program instructions. Examplesof processing circuitry 911 include general purpose central processingunits, microprocessors, application specific processors, and logicdevices, as well as any other type of processing device. In someexamples, processing circuitry 911 includes physically distributedprocessing devices, such as cloud computing systems.

Network interface 901 includes one or more network interfaces forcommunicating over communication networks, such as packet networks, theInternet, and the like. The network interfaces can include one or morelocal or wide area network communication interfaces which cancommunicate over Ethernet or Internet protocol (IP) links. Networkinterface 901 can include network interfaces configured to communicateusing one or more network addresses, which can be associated withdifferent network links. Examples of network interface 901 includenetwork interface card equipment, transceivers, modems, and othercommunication circuitry.

RAM 912 and storage 913 together can comprise a non-transitory datastorage system, although variations are possible. RAM 912 and storage913 can each comprise any storage media readable by processing circuitry911 and capable of storing software. RAM 912 can include volatile andnonvolatile, removable and non-removable media implemented in any methodor technology for storage of information, such as computer readableinstructions, data structures, program modules, or other data. Storage913 can include non-volatile storage media, such as solid state storagemedia, flash memory, phase change memory, magnetic memory, or asillustrated by storage system 960 in this example. RAM 912 and storage913 can each be implemented as a single storage device but can also beimplemented across multiple storage devices or sub-systems. RAM 912 andstorage 913 can each comprise additional elements, such as controllers,capable of communicating with processing circuitry 911.

Software stored on or in RAM 912 or storage 913 can comprise computerprogram instructions, firmware, or some other form of machine-readableprocessing instructions having processes that when executed a processingsystem direct cache node 900 to operate as described herein. Forexample, software drives cache node 900 to receive requests for content,determine if the content is stored in cache node 900, retrieve contentfrom origin servers, transfer content to end user devices, manage datastorage systems for handling and storing the content, identifystenographic portions of network addresses, decode stenographicinformation include in network addresses to perform actions associatedwith the stenographic information, among other operations. The softwarecan also include user software applications. The software can beimplemented as a single application or as multiple applications. Ingeneral, the software can, when loaded into a processing system andexecuted, transform the processing system from a general-purpose deviceinto a special-purpose device customized as described herein.

RAM space 920 illustrates a detailed view of an example configuration ofRAM 912. It should be understood that different configurations arepossible. RAM space 920 includes applications 930, operating system (OS)940, and content RAM cache 950. Content RAM cache 950 includes RAM spacefor temporary storage of content, such as dynamic random access memory(DRAM).

Applications 930 include content interface 931, configuration interface932, and content caching application 935. Content caching application935 handles caching of content and management of storage spaces, such ascontent RAM cache 950 and storage space 965, as well as exchangescontent, data, and instructions via content interface 931 andconfiguration interface 932. Content caching application 935 cancomprise a custom application, Varnish caching software, hypertexttransfer protocol (HTTP) accelerator software, or other content cachingand storage applications, including variation, modifications, andimprovements thereof. Applications 930, OS 940, and address correlations963, address-based functions 964 can reside in RAM space 920 duringexecution and operation of cache node 900, and can reside in systemsoftware storage space 962 on storage system 960 during a powered-offstate, among other locations and states. Applications 930 and OS 940 canbe loaded into RAM space 920 during a startup or boot procedure asdescribed for computer operating systems and applications.

Content interface 931 and configuration interface 932 each allow a userto interact with and exchange data with content caching application 935.In some examples, each of content interface 931 and configurationinterface 932 comprise an application programming interface (API).Content interface 931 allows for exchanging content for caching in cachenode 900 by content caching application 935, and can also receiveinstructions to purge or erase data from cache node 900. Contentinterface 931 can retrieve network and web page content from originservers for delivery to end users. Configuration interface 932 allowsfor altering the configuration of various operational features ofcontent caching application 935. In some examples, configurationinterface 932 comprises a scripting language interface, such as VarnishConfiguration Language (VCL), Perl, PHP, Javascript, or other scriptingor interpreted language-based interfaces. Content interface 931, andconfiguration interface 932 can each communicate with external systemsvia network interface 901 over any associated network links. In furtherexamples, one or more of elements 931-932 are implemented in VCL or VCLmodules.

Content interface 931 can also the handling of functional addressingwith regards to cache node 900. Specifically, when stenographic oranonymized addressing is employed, such as in the examples herein, cachenode 900 can store address correlations 963, which comprises one or moredata structures correlating content 961 and network addresses whichmight include stenographic/anonymized addresses. Moreover, content node900 can perform one or more actions or functions based on receivedstenographic/anonymized addresses. These functions can be stored inaddress-based functions 964 which comprises one or more data structureswith correlations between functions, such as logging, dropping, orredirection functions, and network addresses, such asstenographic/anonymized addresses.

Storage system 960 illustrates a detailed view of an exampleconfiguration of storage 913. Storage system 960 can comprise flashmemory such as NAND flash or NOR flash memory, phase change memory,magnetic memory, among other solid state storage technologies. As shownin FIG. 9, storage system 960 includes system software 962, addresscorrelations 963, address-based functions 964, as well as content 961stored in storage space 965. As described above, system software 962 canbe a non-volatile storage space for applications 930 and OS 940 during apowered-down state of cache node 900, among other operating software.Content 961 includes cached content, such as the web content, which caninclude text, data, pictures, video, audio, web pages, scripting, code,dynamic content, or other network content. In this example, content 961includes network content and web pages associated with one or morewebsites, as indicated by www.gamma.gov, www.alpha.com, andwww.beta.net.

Cache node 900 is generally intended to represent a discrete ordistributed computing system with which at least software 930 and 940are deployed and executed in order to render or otherwise implement theoperations described herein. However, cache node 900 can also representany computing system on which at least software 930 and 940 can bestaged and from where software 930 and 940 can be distributed,transported, downloaded, or otherwise provided to yet another computingsystem for deployment and execution, or yet additional distribution.

FIG. 10 illustrates the internal configuration of control node 1000.Control node 1000 can be an implementation of control elements of acontent delivery network, such as portions of DNS translation nodes,management systems, control nodes, stenography nodes, anonymizationnodes, or other elements, although variations are possible. For example,control node 1000 can be an example of stenography node 115 or DNS node113 node in FIG. 1, control node 415 or DNS node 419 of FIG. 4,anonymization node 615 or routing node 616 of FIG. 6, or other elementsof a CDN or DNS system discussed herein. Control node 1000 includesmanagement interface 1010, communication interface 1020, and processingsystem 1030. Processing system 1030 includes processor 1040 and storagesystem 1050. In operation, processing system 1030 is operatively linkedto management interface 1010, communication interface 1020, and storagesystem 1050. Processing system 1030 is capable of executing software1060 stored in storage system 1050. When executing the software,processing system 1030 drives control node 1000 to operate as describedherein. Control node 1000 can also include other elements, such as userinterfaces, computer systems, databases, distributed storage andprocessing elements, and the like.

Management interface 1010 can comprise software interfaces, applicationprogramming interfaces (APIs), remote user interfaces, terminalinterfaces, and the like. In some examples, management interface 1010 isimplemented by processing system 1030 and communicates over networkinterface 1020. In other examples, management interface 1010 isconfigured to communicate over communication networks, such as packetnetworks, the Internet, and the like. Management interface 1010 caninclude one or more local or wide area network communication interfaceswhich can communicate over Ethernet or Internet protocol (IP) links.Management interface 1010 can include network interfaces configured tocommunicate using one or more network addresses, which can be associatedwith different network links. Examples of management interface 1010include network interface card equipment, transceivers, modems, andother communication circuitry.

Network interface 1020 includes one or more network interfaces forcommunicating over communication networks, such as packet networks, theInternet, and the like. The network interfaces can include one or morelocal or wide area network communication interfaces which cancommunicate over Ethernet or Internet protocol (IP) links. Networkinterface 1020 can include network interfaces configured to communicateusing one or more network addresses, which can be associated withdifferent network links. Examples of network interface 1020 includenetwork interface card equipment, transceivers, modems, and othercommunication circuitry.

Processing system 1030 can be implemented within a single processingdevice but can also be distributed across multiple processing devices orsub-systems that cooperate in executing program instructions. Examplesof processing system 1030 include general purpose central processingunits, microprocessors, application specific processors, and logicdevices, as well as any other type of processing device. In someexamples, processing system 1030 includes physically distributedprocessing devices, such as cloud computing systems.

Storage system 1050 comprises one or more computer-readable media-baseddata storage system, although variations are possible. Storage system1050 can comprise any non-transitory storage media readable by processor1040 and capable of storing at least software 1060. Storage system 1050can include volatile and nonvolatile, removable and non-removable mediaimplemented in any method or technology for storage of information, suchas computer readable instructions, data structures, program modules, orother data. Storage system 1050 can include non-volatile storage media,such as solid state storage media, flash memory, or solid state storagesystem. Storage system 1050 can be implemented as a single storagedevice but can also be implemented across multiple storage devices orsub-systems. Storage system 1050 can comprise additional elements, suchas controllers, capable of communicating with processor 1040.

Software stored on or in storage system 1050 can comprise computerprogram instructions, firmware, or some other form of machine-readableprocessing instructions having processes that when executed byprocessing system 1030 direct control node 1000 to operate as describedherein. The software can also include user software applications. Thesoftware can be implemented as a single application or as multipleapplications. In general, the software can, when loaded into processingsystem 1030 and executed, transform processing system 1030 from ageneral-purpose device into a special-purpose device customized asdescribed herein.

In at least a first example, such as when control node 1000 is employedas stenography node 115 in FIG. 1, control node 415 in FIG. 4, oranonymization node 615 in FIG. 6, the machine-readable processinginstructions comprise functional addressing logic 1070, which caninclude stenographic address generator 1071, anonymized addressgenerator 1072, and correlation logic 1073. Stenographic addressgenerator 1071 can generate network addresses which mark, encrypt,watermark, or otherwise encode information or functions within at leasta portion of network addresses, such as lower-order bits of an IPv6network address. Stenographic address generator 1071 can generate aplurality of addresses and provide these to DNS nodes, cache nodes,routing nodes, control nodes, or other network elements. Anonymizedaddress generator 1072 can generate network addresses which areephemeral or anonymized, such as using lower-order bits of an IPv6network address. Anonymized address generator 1072 can generate aplurality of addresses and provide these to DNS nodes, routing nodes,control nodes, origin server nodes, or other network elements.Correlation logic 1073 can correlate endpoints with the stenographicaddresses or anonymized addresses. For example, when anonymizedaddresses are employed to reach a cache node, then correlations betweenthe cache nodes and the anonymized addresses can be established bycorrelation logic 1073. These correlations can be transferred to routingnodes for routing of anonymized traffic to proper cache nodes. Whenstenographic addresses are employed, then correlation logic 1073 canestablish correlations between the stenographic addresses and encodedfunctions or encoded information. These correlations can be transferredto DNS nodes, cache nodes, routing nodes, control nodes, or othernetwork elements.

In at least a second example, control node 1000 provides route selectionfeatures which can drive a DNS system to return a particular IP addressresponsive to DNS queries or DNS lookup requests from end user devices.For example, when control node 1000 is employed as DNS node 113 of FIG.1, DNS node 419 of FIG. 4, or DNS node 619 of FIG. 6, domain nametranslation can be handled by control node 1000. In other examples,control node 1000 can be employed as routing node 616 in FIG. 6 and canperform route selection for anonymized addresses. The machine-readableprocessing instructions comprise routing logic 1080, which can includeDNS translator 1081 and address router 1082. DNS translator 1081translates domain names included in DNS queries or DNS translationrequests into network addresses, which can include translation intostenographic addresses or anonymized addresses. DNS translator 1081 canmaintain one or more lists of address translations, such as whenrotating, ephemeral, or other address configurations are employed. Whencontrol node 1000 is employed in a DNS node, DNS translator 1081 cantranslate domain names into network addresses which include stenographicor anonymized portions and transfer the network addresses to endpoints.Furthermore, DNS translator 1081 can aid in localization or isolation ofattack traffic when DNS requests are logged, dropped, or otherwisehandled in accordance with attack mitigation actions. Address router1082 can maintain one or more data structures which relates anonymizedaddresses to cache nodes, such as anonymized addresses used in contentrequests which are related to identifiers for cache nodes. Addressrouter 1082 can receive these relationships from other control nodes.When employed as a routing node, such as routing node 616 of FIG. 6,Address router 1082 can be included to handle routing of contentrequests from end user devices as well as content deliveries from originsystems.

The included descriptions and figures depict specific embodiments toteach those skilled in the art how to make and use the best mode. Forthe purpose of teaching inventive principles, some conventional aspectshave been simplified or omitted. Those skilled in the art willappreciate variations from these embodiments that fall within the scopeof the invention. Those skilled in the art will also appreciate that thefeatures described above can be combined in various ways to formmultiple embodiments. As a result, the invention is not limited to thespecific embodiments described above, but only by the claims and theirequivalents.

What is claimed is:
 1. A method of operating a content delivery network(CDN) comprising a plurality of cache nodes that cache content fordelivery to end user devices, the method comprising: establishingaddress translations which translate domain names into network addressesusable by the end user devices for reaching content at the cache nodes,with portions of the network addresses comprising stenographicinformation; responsive to domain name translation requests from the enduser devices, providing ones of the network addresses; receiving contentrequests transferred by the end user devices that comprise the networkaddresses; performing one or more actions based on the stenographicinformation in the network addresses.
 2. The method of claim 1, whereinthe network addresses comprise Internet Protocol version 6 (IPv6)network addresses, and wherein the portions of the network addressescomprising stenographic information are included in at least a lower 64bits of the network addresses.
 3. The method of claim 2, wherein thenetwork addresses comprise routing information in at least an upper 64bits of the network addresses, the routing information configured todirect the content requests to at least one cache node that caches thecontent.
 4. The method of claim 1, wherein performing the one or moreactions based on the stenographic information comprises processing thestenographic information included in the network addresses of thecontent requests to identify DNS nodes that serviced the domain nametranslation requests.
 5. The method of claim 1, wherein performing theone or more actions based on the stenographic information comprisesprocessing the stenographic information included in the networkaddresses of the content requests to identify geographic locationsassociated with the content requests.
 6. The method of claim 1, furthercomprising: providing first ones of the network addresses to a firstdomain name system (DNS) node, the first ones of the network addressescomprising stenographic information selected to identify the first DNSnode; providing second ones of the network addresses to a second DNSnode, the second ones of the network addresses comprising stenographicinformation selected to identify the second DNS node; and whereinperforming the one or more actions based on the stenographic informationcomprises processing the stenographic information included in thenetwork addresses of the content requests to identify which among thefirst DNS node and the second DNS node serviced the domain nametranslation requests.
 7. The method of claim 1, wherein the stenographicinformation comprises instructions for cache nodes which receive thecontent requests, and further comprising: in ones of the cache nodesthat receive the content requests, identifying the instructions andresponsively performing one or more actions commensurate with theinstructions.
 8. The method of claim 7, wherein the instructionsindicate to drop traffic associated with the content requests thatindicate the network addresses comprising the stenographic information.9. The method of claim 7, wherein the instructions indicate to logtraffic associated with the content requests that indicate the networkaddresses comprising the stenographic information.
 10. A contentdelivery network (CDN) having a plurality of cache nodes that cachecontent for delivery to end user devices, the CDN comprising: astenography node configured to establish address translations whichtranslate domain names into network addresses usable by the end userdevices to reach content at the cache nodes, with portions of thenetwork addresses comprising stenographic information; the stenographynode configured to provide the address translations to at least onedomain name system (DNS) node that provides ones of the networkaddresses responsive to domain name translation requests from the enduser devices; at least one of the cache nodes configured to receivecontent requests transferred by the end user devices that comprise thenetwork addresses, and perform one or more actions based on thestenographic information in the network addresses.
 11. The CDN of claim10, wherein the network addresses comprise Internet Protocol version 6(IPv6) network addresses, and wherein the portions of the networkaddresses comprising stenographic information are included in at least alower 64 bits of the network addresses.
 12. The CDN of claim 11, whereinthe network addresses comprise routing information in at least an upper64 bits of the network addresses, the routing information configured todirect the content requests to at least one cache node that caches thecontent.
 13. The CDN of claim 10, comprising: the at least one of thecache nodes configured to process the stenographic information includedin the network addresses of the content requests to identify DNS nodesthat serviced the domain name translation requests.
 14. The CDN of claim10, comprising: the at least one of the cache nodes configured toprocess the stenographic information included in the network addressesof the content requests to identify geographic locations associated withthe content requests.
 15. The CDN of claim 10, comprising: thestenography node configured to provide first ones of the networkaddresses to a first domain name system (DNS) node, the first ones ofthe network addresses comprising stenographic information selected toidentify the first DNS node; the stenography node configured to providesecond ones of the network addresses to a second DNS node, the secondones of the network addresses comprising stenographic informationselected to identify the second DNS node; and the at least one of thecache nodes configured to process the stenographic information includedin the network addresses of the content requests to identify which amongthe first DNS node and the second DNS node serviced the domain nametranslation requests.
 16. The CDN of claim 10, wherein the stenographicinformation comprises instructions for cache nodes which receive thecontent requests, and further comprising: the at least one of the cachenodes configured to identify the instructions and responsively performone or more actions commensurate with the instructions.
 17. The CDN ofclaim 16, wherein the instructions indicate to drop traffic associatedwith the content requests that indicate the network addresses comprisingthe stenographic information.
 18. The CDN of claim 16, wherein theinstructions indicate to log traffic associated with the contentrequests that indicate the network addresses comprising the stenographicinformation.
 19. A method of operating a stenography node of a contentdelivery network that caches content for delivery to end user devices,the method comprising: establishing address translations which translatedomain names into network addresses used for reaching content atselected cache nodes, with portions of the network addresses comprisingstenographic information used to distinguish among a plurality of domainname system (DNS) nodes which provide ones of the network addressesresponsive to domain name translation requests from the end userdevices; instructing one or more cache nodes to perform one or moreactions based on the stenographic information in the network addressesresponsive to receiving content requests transferred by the end userdevices that comprise the network addresses.
 20. The method of claim 10,wherein the network addresses comprise Internet Protocol version 6(IPv6) network addresses, wherein the portions of the network addressescomprising stenographic information are included in at least a lower 64bits of the network addresses, and wherein the network addressescomprise routing information in at least an upper 64 bits of the networkaddresses, the routing information configured to direct the contentrequests to at least one cache node that caches the content.